This Phase IV, open-label, prospective clinical trial assesses SA-LAIV, testing whether the immunogenicity of SA-LAIV is non-inferior to that of HCWA-LAIV, as well as evaluating the feasibility of utilizing group administration for SA-LAIV. Subjects will be enrolled into one of two major treatment arms: HCWA-LAIV (Estimated N = 550) and SA-LAIV (Estimated N = 550). Enrollment into each major treatment arm will be stratified by study site. Enrollment in the HCWA-LAIV and SA-LAIV treatment arms may occur concurrently at each site. Subjects enrolling in the study will be randomized to HCWA or SA, and within the SA arm to either individual self-administration, or group administration. Specifically, following self-administration of LAIV to 190 individual subjects, 180 subjects will be vaccinated in 36 groups of 5 and 180 subjects will be vaccinated in 18 groups of 10. All vaccinations in the SA-LAIV arm will be given under the direction and supervision of a research staff member who is trained to administer LAIV vaccines. Following immunization all subjects will return for one visit at approximately 28 (± 7) days for follow-up.